Draw-clamp.



H. A. KNOKE.

DRAW CLAMP.

APPLICATION FILED MAR. 5. 1909.

Patented Jan. 11,1910.

UNITED STATES PATENT OFFICE.

HERMAN A. KNOKE, OF CHICAGO, ILLINOIS, ASSIGNOR TO M. B. JOSEPH AND H. H. JOSEPH, OF CHICAGO, ILLINOIS.

DRAW- CLAMP.

To all whom "it may concern:

Be it known that I, HERMAN A. KNoKn, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Draw-Clamps, of which the following is a specification.

My invention relates to an improvement in draw-clamps of the type most commonly used by carpenters and cabinet makers for clamping large flat wooden sections of vary ing sizes, such as desk or table tops, and the like, which ordinarily comprise several strips of Wood glued together, and for holding such sections in clamped condition during the time necessary for the glue to thoroughly set and harden.

The object of my invention is to improve, in matters of detail, the construction of clamps of this class, and thereby render them more effective in their purpose and more readily adjustable.

In the accompanying drawing, Figure 1 shows my improved clamp by a broken perspective view; Fig. 2 is an enlarged broken view in sectional elevation taken at the line 2, Fig. 1, and showing one position of the head by dotted lines, and Fig. 3 is a view in perspective of the clamping jaw, retainingwasher and the forward-end portion of the clampscrew, showing these parts in unassembled relation.

The usual metal bar 4 is provided at intervals in its lower edge with notches 5. An adjustable head 6 is mounted on the bar to slide freely thereon as it is adjusted from one position to another, and is confined against withdrawal from the bar by a pin 77 extending through the latter near one end and projecting beyond each of its side faces.

The head 6 is formed with a heel-portion 7 projecting to the rear of its face, adapted to bear on the upper edge of the bar, and with a toe 8 beneath the same slightly in advance of the perpendicular plane of the face of the head and adapted to enter any notch 5, and to hold the head in locked engagement with the bar. A recess is formed in the head above the bar to extend backwardly some distance from the face, and a spring 9 is let into the head near its face and bears against the bar to tend to tilt it and thus normally maintain the toe 8 in engagement with a notch. A yoke 10 is Specification of Letters Patent.

Application filed March 5, 1909.

Patented Jail. 11, 1910. Serial No. 481,465.

rigidly fastened on the bar at its forward end as by rivets 11 passing through ears projecting from the yoke at opposite sides of the bar and two similarly internally threaded bearings 12 extend to aline with each other from the yoke above the bar. The clamp-screw 13 works in these two bear ings which afford to it a firm hold, preventing undue play of the screw, and effectually and truly guiding it without binding, in its forward and backward course in rotating. The screw is provided with a crank 14 at its outer end by which to operate it, while its forward end terminates in a head 15 which latter is formed by reducing the rod to provide a circumferential groove or neck 16', as clearly shown in Fig. 3. A clamping-jaw 17 slotted at its lower edge, as at 18, to embrace the bar for guiding purposes, is connected with the screw and mounted to slide upon the bar as shown in Fig. l, and is provided with a boss 19 projecting from its rear face. A socket 20 is formed in the boss of approximately the size of the screw-head 15, and extending be yond the rear end of the boss, at intervals about it, are lugs or fingers 21 preferably formed integrally therewith.

For connecting the clampingjaw with the screw, a bifurcated or slotted washer 22 (see Fig. 3), is employed by causing it to straddle the screw at the groove 16, the head 15 is then inserted in the socket 20 thereby positioning the washer between the projecting ends of the fingers with its face against the boss. The lugs are formed of suflicient length to project beyond the washer in the described position, where their ends are bent at right-angles, as shown in Fig. 1.

The bar 4 is ordinarily several feet in length and in using the device, the clamping-jaw is first run back into close proximity to the yoke, then the head is adjusted along the bar to suit the width of the work to be clamped, whereupon the clamping-jaw is adjusted in the usual manner. For adjusting the head along the bar it is first depressed to compress the spring and then rocked forward to the position indicated in dotted lines in Fig. 2, which movement results in disengagement of the toe 8 from its registering slot 5, when the head is free to be slid along the bar until the proper point has been reached for the desired adjustmcnt. The presslnie is then relieved and the spring forces the toe into a slot (if in registration therewith) and if not, the head may be readily slid either forward or back ward until the toe snaps into a notch by the action of the spring.

The socket 20 is bored in the boss 19 which projects from the rear face of the clamping jaw 17, and the outer end of said boss is surfaced by one and the same tool, thus affording substantial and smooth seats for the head 15 of the screw 13, the washer 22 being also provided with smooth surfaces. and when the parts are secured together in working relation the clamping jaw is firmly held in position at right angles to the screw while the latter is permitted freedom of rotation, due to the minimum of friction, owing to the smooth surfaces of the contacting parts.

An important advantage of the hexagonal-shaped washer is that when such washer is clamped in position by the fingers 21 against its hexagonal faces, it is pre vented from turning, which would not be the case were such washer of circular form, in which case it would only be prevented from turning by the frictional contact between it and the fingers 21. Under certain strains a round washer would be caused to turn, and such continued movement would cause its edge to cut through, or into the fingers, destroying their grip, and so weakening them that they might become broken upon slight jar or strain.

My improved means for connecting the screw with the clamping-jaw are especially effective in preventing wear on the parts, thereby preventing any wabbling action between them and enhancing the effectiveness and durability of the device; although the engagement with each other of the parts permits suflicient lateral play to the jaw 17 to enable it to conform to irregularities or inclinations on the surface of the work against which it bears.

lVhat 1 claim as new and desire to secure by Letters Patent is l. A draw-clamp comprising, in combination, a notched bar, a head adjustable on said bar to engage the notches therein, a yoke secured on one end of the bar and having alining bearings extending from it, a handle-equipped screw working in said bearings and terminating at its forward end in a head, with a neck adjacent thereto, a clamping-jaw slidably mounted on the bar and containing in its rear side a socket, in which said screw-head is rotatably confined, a slotted hexagonal-shaped washer straddling said neck, and fingers projecting beyond the rear end of said socket and bent over said washer and confining the same in place.

2. A draw-clamp comprising, in combination, a notched bar, a head adjustable on said bar to engage the notches therein, rigid alining bearings on one end of the bar, a hai'idle-equipped screw working in said bearings and terminating at its forward end in a head, with a neck adjacent thereto, a clamping-jaw slidably mounted on the bar and having projecting from its rear face a boss containing a socket and provided at intervals about it with lugs projecting beyond its rear end to form. fingers, and a slotted hexagonal-shaped washer straddling said neck with the screw head in said socket and said fingers projecting beyond the washer and bent over it to hold it in place.

3. A draw-clamp comprising, in combination, a notched bar, a head adjustable on said bar to engage the notches therein, a screw rotatably supported on the opposite end of the bar and terminating at its forward end in a head with a neck adjacent thereto, a clamping-jaw on the bar provided on its rear side with a boss containing a socket in which said head is rotatably confined, a slotted hexagonal-shaped washer straddling said neck, and fingers extending from said boss and engaging said washer to secure it in place.

HER-MAN A. KNOKE.

In presence of- R. Sonanrnn, L. Harmer. 

